Regular guards appear as men in grey suits of an indeterminate material, with an eyepiece equipped with two green lenses. They have pipes on their backs connected to a tank for breathing. Their suits appear lighter in Nitrome Must Die, almost light green.
Guards first appear in level 1 are encountered inside and outside the fortress of steam. In level 8, it is said guards are mutant men. When Dirk comes close to the guards, a green exclamation point will appear above their heads and they will run toward Dirk Valentine, trying to hit him. Guards will run back and forth, turning at edges.
Guards are some times seen sitting down and eating, talking with each other, or making hand gestures and appearing to talk alone. Oddly, when two guards are talking with each other and one is shot, the guard that is not shot will still continue to make gestures and talk as if the guard was still there. Also, if the game is paused while a guard is present on the screen and then the game is unpaused, a green exclamation point will appear above the guards head though it will not move toward Dirk Valentine.
To kill a guard, the player must shoot at them. They will die and grant the player 10 points. Baron Battenberg deploys a single Guard from his steam-powered Batter-Berger on level twenty-four, the second boss fight.
Guards appear in Nitrome Must Die, being lighter in colour and acting no different then they did in Dirk Valentine. When they exit a pipe, they will run around, falling down platforms and turning at walls.
They have the ability to run faster than most enemies, appear often alongside other enemies or groups of guards. They have no attack, and can only harm the player by running into them, which puts them in danger of being shot and killed before reaching their target.
- Horror skin - A guard appears emerging from the ground, with worms in its head.
- Steampunk skin - A guard appears chasing Dirk Valentine.
- Steamlands - A guard appears buried in the ground.
- One of the noises that the guards make when they die is a sound effect called the Wilhelm scream.